package fk.androiddemo_009; import android.os.Environment; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; /** * Created by Administrator on 2016/9/14. */ public class FileUtils { private String SDCardRoot; public FileUtils(){ //得到當(dāng)前外部存儲(chǔ)裝備的目錄 SDCardRoot= Environment.getExternalStorageDirectory()+File.separator; //File.separator為文件分隔符”/“,方便以后在目錄下創(chuàng)建文件 } //在SD卡上創(chuàng)建文件 public File createFileInSDCard(String fileName,String dir) throws IOException { File file=new File(SDCardRoot+dir+File.separator+fileName); file.createNewFile(); return file; } //在SD卡上創(chuàng)建目錄 public File createSDDir(String dir)throws IOException{ File dirFile=new File(SDCardRoot+dir); dirFile.mkdir();//mkdir()只能創(chuàng)建1層文件目錄，mkdirs()可以創(chuàng)建多層文件目錄 return dirFile; } //判斷文件是不是存在 public boolean isFileExist(String fileName,String dir){ File file=new File(SDCardRoot+dir+File.separator+fileName); return file.exists(); } //將1個(gè)InoutStream里面的數(shù)據(jù)寫入到SD卡中 public File write2SDFromInput(String fileName,String dir,InputStream input){ File file=null; OutputStream output=null; try { //創(chuàng)建目錄 createSDDir(dir); //創(chuàng)建文件 file=createFileInSDCard(fileName,dir); //寫數(shù)據(jù)流 output=new FileOutputStream(file); byte buffer[]=new byte[4*1024];//每次存4K int temp; //寫入數(shù)據(jù) while((temp=input.read(buffer))!=⑴){ output.write(buffer,0,temp); } output.flush(); } catch (Exception e) { System.out.println("寫數(shù)據(jù)異常："+e); } finally{ try { output.close(); } catch (Exception e2) { System.out.println(e2); } } return file; } }

package fk.androiddemo_009; import java.io.BufferedReader; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.URL; /** * Created by Administrator on 2016/9/14. */ public class HttpDownloader { String line=null; StringBuffer strBuffer=new StringBuffer(); BufferedReader bufferReader=null; //下載小型的文檔文件，返回文檔的String字符串 public String downloadFiles(String urlStr){ try { InputStream inputStream=getInputStreamFromUrl(urlStr); bufferReader=new BufferedReader(new InputStreamReader(inputStream)); while((line=bufferReader.readLine())!=null){ strBuffer.append(line+'\n'); } } catch (Exception e) { strBuffer.append("something is wrong!!"); System.out.println("讀取數(shù)據(jù)異常:"+e); } finally{ try { bufferReader.close(); } catch (Exception e) { strBuffer.append("something is wrong!!"); e.printStackTrace(); } } return strBuffer.toString(); } //可以下載任意文件，例如MP3，并把文件存儲(chǔ)在制定目錄（⑴：下載失敗，0：下載成功，1：文件已存在） public int downloadFiles(String urlStr,String path,String fileName){ try { FileUtils fileUtils=new FileUtils(); if(fileUtils.isFileExist(fileName,path)) return 1;//判斷文件是不是存在 else{ InputStream inputStream=getInputStreamFromUrl(urlStr); File resultFile=fileUtils.write2SDFromInput(fileName,path,inputStream); if(resultFile==null) return ⑴; } } catch (Exception e) { System.out.println("讀寫數(shù)據(jù)異常:"+e); return ⑴; } return 0; } public InputStream getInputStreamFromUrl(String urlStr)throws IOException { //創(chuàng)建1個(gè)URL對(duì)象 URL url=new URL(urlStr); //創(chuàng)建1個(gè)HTTP鏈接 HttpURLConnection urlConn=(HttpURLConnection)url.openConnection(); //使用IO流獲得數(shù)據(jù) InputStream inputStream=urlConn.getInputStream(); return inputStream; } }

package fk.androiddemo_009; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; //1,在Manifest文件中注冊(cè)Internet和讀寫SDCard的權(quán)限 //2,下載不能在主線程中進(jìn)行，要開分線程 public class MainActivity extends AppCompatActivity implements View.OnClickListener{ Button but1,but2; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); but1=(Button)findViewById(R.id.but1); but1.setOnClickListener(this); but2=(Button)findViewById(R.id.but2); but2.setOnClickListener(this); } @Override public void onClick(View v) { if(v==but1){ new downloadFileThread().start(); }else if(v==but2){ new downloadMP3Thread().start(); } } class downloadFileThread extends Thread{ public void run(){ HttpDownloader httpDownloader=new HttpDownloader(); String fileData=httpDownloader.downloadFiles("http://mystudy.bj.bcebos.com/AndroidDemo_009.xml"); System.out.println(fileData); } } class downloadMP3Thread extends Thread{ public void run(){ HttpDownloader httpDownloader=new HttpDownloader(); int downloadResult=httpDownloader.downloadFiles( "http://fengkui.bj.bcebos.com/%E8%B6%B3%E9%9F%B3.mp3","BoBoMusic","足音.mp3"); System.out.println("下載結(jié)果："+downloadResult); } } }